Species:
Retroelphidium obesum >
Genus:
Retroelphidium >
Subfamily:
Elphidiinae >
Family:
Elphidiidae >
Superfamily:
Rotalioidea >
Order:
Rotaliida >
Subclass:
Rotaliana >
Class:
Globothalamea >
Phylum:
Foraminifera >
Kingdom:
Chromista >
Unranked:
Biota >